66 



ZEACRINUS BLAIKI, n. sp. 



Plate IV, Fig. 5, azygous side; Fig. 6, opposite side of same 

 specimen, showing part of the proboscis. 



Species below medium size. Calyx low, basin-shaped, two 

 and a half times as wide as high, depressed at the base, 

 plates convex, sutures distinct, surface granular. Column 

 small and round. 



Basals form a disc one-half larger than the diameter of the 

 column, and, in plain view, as seen from below. Subradials 

 wider than high, and forming, with the basals, a low cup. 

 First radials wider than long, pentagonal, truncated the entire 

 width above, and separated from the brachials by a gaping 

 suture. A single brachial, about as long as wide, rounded and 

 contracted, in the middle, and axillary, supports upon its upper 

 sloping sides, in each radial series, the free arms. The proxi- 

 mal arm, on the left of the azygous area, bifurcates on the 

 sixth plate, and the proximal side again on the ninth plate, 

 and the distal side bifurcates on the fourth plate, and the dis- 

 tal branch on the eighth plate, which gives to this ray six 

 arms. The ray opposite the azygous area bifurcates, on one 

 branch, on the fourth plate, and, on the other, on the seventh 

 plate, which gives to it four arms. One of the lateral rays 

 bifurcates, on each branch, on the sixth plate, which gives to 

 it four arms. The other two rays are broken off below the 

 first bifurcation, in our specimens, but we presume the lateral 

 rays are alike, and the ray on the right of the azygous area 

 the same as the one on the left, and if so, the species has 

 twenty- four arms. The arms are short, round and composed 

 of short plates. Pinnules small. 



The azygous area is wide, ovate and exposes ten plates ar- 

 ranged alternately, as usual, in this genus. The first one is 

 about half as large as a subradial, rests upon one sloping side 

 of a subradial and abuts another, separates the first radial, on 

 the right, from the second azygous plate and is truncated 1 y 

 the third plate. The second one is about the size of the first, 

 truncates a subradial, separates the first radial, on the left, 

 and the lower part of the brachial, from the first and third 

 plates and is truncated above by the fourth and fifth plates. 

 The fourth, fifth and sixth plates are in one range crossing 



